The invention relates to safety heat exchanger for a combination of a heat pump with a device of a drinking water supply facility, with a primary circulation loop with drinking water, a secondary safety circulation loop with an anti-freeze material that does not pose a health risk, and a tertiary circulation loop with a coolant.
DE 102004061441 B4 discloses a heat exchanger for use in a drinking water sanctuary. For safety reasons, a third intermediate circulation loop is proposed in order to be able to operate the primary circulation with drinking water, with the intent to protect the drinking water in drinking water sanctuaries.
DE 2834442 A1 already disclosed a combination of a drinking water supply facility with a heat exchanger for obtaining heat. For obtaining domestic heat based on a heat pump system, a partial quantity of water is to be removed from the pipe network of a central water supply facility, from which heat is removed with a heat exchanger. As a precaution, a heat storage device is provided between the heat pump and the heat exchanger of the partial water quantity withdrawn from the pipe network. The storage device should ensure that heat generation during the night is independent for a limited time, when a very low flow velocity can be expected in the pipes of the central water supply facility. The intermediate storage device is unable to prevent the coolant from coming into contact with the drinking water in the event of a leak.
DE 2930484 A1 also proposes to use a heat pump in a drinking water facility. The heat exchanger is integrated in a drinking water pipe with fittings. The main water pipe should be arranged as a loop so as to ensure continuous heat supply in the main water pipe. A circulation pump can be used to circulate the drinking water in the main water supply pipe arranged in the loop. The circulation pump is controlled depending on the temperature of the drinking water.
DE 792 7266 U1 discloses a condenser for heat pumps with an inner tube surrounded by an outer tube. The enclosed annular space is filled with water and connected with an overpressure safety valve and a switching device.
AT 375770 B also discloses any double-walled cooling coil with a pressure indicator, wherein the cooling coil contains water as separating fluid. The waste heat from oil is to be used for heating service water which should not come into contact with the oil. The pressure indicator is not suitable for a unpressurized primary medium is not protected from freezing.
DE 2926578 A1 relates to a safety heat exchanger for heating drinking water that is to be separated from the coolant loop. Direct heating of the drinking water should be avoided, because the coolant and the drinking water would then only be separated by a single wall. This is not in compliance with increased safety requirements in drinking water supply.
In DE 2926578 A1, at least one heat pipe is provided for heat transfer, wherein the end of the heat pipe located outside the fluid container is arranged in a coolant vessel through which a coolant flows. The coolant vessel is connected with the fluid container by way of a double wall. The heat pipe extends through the double wall. This arrangement forms a safety heat exchanger which ensures separation of the coolant from the drinking water and prevents coolant from entering the fluid. The safety arrangement is monitored to show indirectly a decrease in efficiency in the event of a leak.
In the closed heat pipe circulation loop, an intermediate circulation loop with an extremely high conductivity is connected between the coolant and the drinking water. The intermediate circulation loop is formed by heat pipes. The heat pipes are either evacuated or filled with water. However, the heat pipes may also be filled with ethanol. In this way, the heat pipe has a fill which is either neutral with respect to the drinking water or harmless.